Zootaxa, Mollusca, Polyplacophora, Lepidopleuridae

Notes on Fossil Chitons. 1. A new species of Lepidopleurus (Mollusca: Polyplacophora) from the Pleistocene of Salice (Sicily, Italy)

BRUNO DELL’ANGELO1 & ANTONIO BONFITTO2 1 via Mugellese 66D, 59100 Prato, Italy. e-mail: [email protected] 2 Museo di Zoologia dell’Universita’ di Bologna, Via Selmi 3, 40126 Bologna, Italy. e-mail: [email protected]

Abstract

A new species of Polyplacophora (Mollusca) has been found in the Salice outcrop, in the Peloritain Mountains (Sicily, Italy), is attributed to the early Pleistocene. Lepidopleurus (Leptochiton) salicensis n.sp. is characterized by its uniformly sculptured tegmentum, with (well) raised, randomly distributed, neatly separated rounded/polygonal granules. The new species is compared with Lepi- dopleurus (Leptochiton) alveolus (M.Sars MS, Lovén, 1846), from the North Atlantic, and Lepi- dopleurus (Leptochiton) tavianii Dell’Angelo, Landau & Marquet, 2004, from the Pliocene of Estepona (Málaga, Spain).

Key words: Mollusca, Polyplacophora, Lepidopleuridae, Pleistocene, new species, Italy

Introduction

The Salice outcrop, attributed to the early Pleistocene by Bonfiglio (1969), has already been discussed by Seguenza (1876), and is situated in the Tyrrhenian zone of the Peloritani Mountains, at an elevation of about 340 m. The top of the hill, where the former Salice military fort (locality “Coilare”) is situated, is particularly rich in fossils, and is composed of upper bathyal sediments. Brachiopods (Gaetani & Saccà 1983, 1984), Anthozoa (Micali & Villari 1991) and molluscs (Micali & Villari 1989, 1990, 1991) have previously been described from the Salice outcrop. The only chiton reported from this site is Lepidopleurus (Leptochiton) sarsi (Kaas, 1981) (Dell’Angelo & Palazzi 1989). Numerous isolated valves have been recovered from sieving large amounts of sediment, resulting in the discovery of a previously undescribed species of Lepidopleurus (Leptochiton).

Accepted by D.L. Geiger: 30 Dec. 2004; published: 17 Jan. 2005 1 ZOOTAXA The following abbreviations are used to identify the repositories of material: 821 MZB Zoological Museum of Bologna University (Italy); BDA B. Dell’Angelo Collection, Prato (Italy).

Systematics

Class POLYPLACOPHORA Gray, 1821 Order NEOLORICATA Bergenhayn, 1955 Suborder LEPIDOPLEURINA Thiele, 1910 Superfamily LEPIDOPLEUROIDEA Pilsbry, 1892 Family LEPIDOPLEURIDAE Pilsbry, 1892 Genus Lepidopleurus Risso, 1826

Type species: Chiton cajetanus Poli, 1791, by subsequent designation by Herrmannsen 1846: 582.

Subgenus Leptochiton Gray, 1847

Type species: Chiton cinereus Montagu, 1803, non Linnaeus, 1767 (= Chiton asellus Gmelin, 1791), by subsequent designation by Gray 1847: 127.

Lepidopleurus (Leptochiton) salicensis n.sp. (Figures 1–8)

Diagnosis. Valves solid. Tegmentum uniformly sculptured with well raised, neatly separated rounded/polygonal granules, randomly arranged. Description. Head valve semi-oval. Intermediate valves broadly rectangular, back evenly rounded, moderately elevated (intermediate valve, height/width 0.51), front margin slightly convex, side margins rounded, hind margin straight, apices inconspicuous, lateral areas not raised. Tail valve semicircular, anterior margin almost straight, mucro not promi- nent, subcentral, postmucronal slope concave. Tegmentum uniformly sculptured with well raised, neatly separated roundish/polygonal granules, randomly arranged, diameter about 70–90 µm. The aesthetes are not clearly visible, a central one and 2–3 others (but there should be more) may be identified around the border of some granules.

2 © 2005 Magnolia Press DELL’ANGELO & BONFITTO Articulamentum without insertion laminae. On the ventral side of the intermediate ZOOTAXA valves the posterior area clearly presents an expanded central zone, with a bisinuate ante- 821 rior margin. Apophyses small, largely incomplete in the material examined, but probably sharply triangular, widely separated by a large jugal sinus.

FIGURES 1–8: Lepidopleurus (Leptochiton) salicensis n.sp. Fig. 1. Holotype (MZB31028), intermediate valve, scale bar = 1 mm. Fig. 2. holotype, detail of sculpture, scale bar = 100 µm. Fig. 3. holotype, outline, scale bar = 1 mm. Fig. 4. holotype, ventral view, scale bar = 1 mm. Fig. 5. paratype, tail valve, lateral view, scale bar = 1. Fig. 6. paratype tail valve, granules, scale bar = 100 µm; Fig. 7. mm paratype (MZB31029), tail valve, scale bar = 1 mm; Fig. 8. paratype (MZB31029), head valve, scale bar = 1 mm.

FIGURES 9–12: Lepidopleurus (Leptochiton) tavianii Dell’Angelo, Landau & Marquet, 2004, intermediate valve, Holotype, Velerín Carretera (Estepona, Málaga, Spain). Fig. 9. scale bar = 500 µm. Fig. 10. outline, scale bar = 500 µm. Fig. 11. detail of sculpture, scale bar = 50 µm. Fig. 12. granules, scale bar = 10 µm FIGURES 13–16: Lepidopleurus (Leptochiton) alveolus (M.Sars MS, Lovén, 1846), intermediate valve, Sula Ridge (Norway), dredged at –215m. Fig. 13. scale bar = 1 mm. Fig. 14. outline, scale bar = 1 mm. Fig. 15. scale bar = 500 µm. Fig. 16. detail of sculpture, scale bar = 50 µm.

Type material. Holotype: MZB31028 (1 intermediate valve). Paratypes: MZB31029 (1 head and 1 tail valves); BDA 4662 (2 intermediate and 2 tail valves)

4 © 2005 Magnolia Press DELL’ANGELO & BONFITTO Type locality. Salice (Messina province, Sicily, Italy). ZOOTAXA Type stage. Early Pleistocene. 821 Etymology. From the site of Salice. Remarks. The genus Lepidopleurus (Leptochiton) is characterized by valves lacking insertion plates, the sutural laminae (apophyses) small and neatly separate, the tegmentum uniformly granulated, and the girdle narrow, covered with scales or with scales and spi- cules ( Kaas & Van Belle 1985; Dell’Angelo & Smriglio 1999). The granules are generally of small size, with rather regularly arranged aesthetes, and can be arranged in radial or lon- gitudinal series, quincuncially or randomly distributed. Lp. (Lc.) salicensis n.sp. is characterized by the tegmental sculpture consisting of randomly arranged granules. Another species having the same kind of tegmental sculpture as L. salicensis, is Lp. (Lc.) tavianii Dell’Angelo, Landau & Marquet, 2004, known from the Pliocene of Este- pona (Málaga, Spain) (Dell’Angelo, Landau & Marquet 2004: 29, pl.1 figs 1–8, pl.2 figs 1,5), where, however, the granules are characterized by a fungiform section and are arranged in a beehive structure (figs 9–12), not the random distribution seen in L . salicensis. Also Lp. (Lc.) alveolus (M. Sars MS, Lovén, 1846), a species living in North Atlantic and not known as fossil (Kaas & Van Belle 1985: 36. fig. 14), has a tegmentum sculptured with neatly separated rounded to oval, raised granules, arranged quincuncially (fig. 16) , but the granules are more oval and of different shape (compare fig. 2 and fig. 16) , with a characteristic arrangement of aesthetes (fig. 16).

Acknowledgements

The authors thank Stefano Palazzi (Modena, Italy), Salvatore Ventimiglia (Messina, Italy) and Alberto Villari (Messina, Italy), for the help in the trips to the Salice outcrop.

References

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